Method of making latch needles



G. W. MAYO ET AL METHOD OF MAKING LATCH NEEDLES Filed May 20, 1927 March31, 1931.

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Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE GEORGE W. MAYO ANDDELBERT F. MORSE, F LACONIA, NEW HAMPSHIRE METHOD OF MAKING LATCHNEEDLES Application filed May 20,

This invention aims to provide an improved method of making latchknitting machine needles.

In the accompanying drawings is shown an illustrative embodiment of theinvention,

wherein:

Fig. 1 is a side elevation of a needle produced by the method hereindescribed with produced thereby comprises a body 1 having the usual hook3 at one end adjacent to which is pivoted at 5 a latch 7 which operatesat times to close said hook for the purpose of casting off a loop thathas previously been formed upon the needle. The latch 7 is pivoted tothe needle body 1 within a slot 9 extending longitudinally of said body,said slot providing thin supporting members 11 on opposite sides of thelatch.

In its final state the pivot pin 5 desirably has an enlarged centraljournal portion 13 which loosely fits a relatively large perforation 15in the latch 7, thereby permitting the latch to turn freely thereon,while the end portions 17 of said pivot pin, which are smaller indiameter than the body 5, occupy relatively smaller perforations 19formed in the side portions 11 of the needle body. The smaller portions17 are brazed to the side members 11 so as to prevent any likelihood oflooseness occurring between the pivot and the needle body which wouldeventually permit the pivot to move longitudinally in the needle bodyand project slightly at the end to catch upon the fibres of the yarn andso produce a rough ap earance in the finished fabric. I r Desire ly theperforations 19 areoutward- 1y flared or countersunk as shown at 20 andthe ends of the pivot pin 5 are headed at 21 to substantially fill saidcountersunk or outwardly flaring portions and these headed portions arebrazed to the needle body.

The enlarged pivot portion 13 provides shoulders 23 which engage theinner adjacent faces of the sideportions 11 and assist in preventinglongitudinal movements of the pivot pin should by chance the ends ofsaid pin become loosened by wear. Furthermore, by enlarging the bearingportion of the pin which is usually the first part to wear out, the lifeof the needle will be greatly prolonged.

In order that the needle embodying this invention may quickly andeconomically be made we provide a method of making the same whichincludes the insertion or forcing of a pin 6 of substantially uniformdiameter throughout, through the aligned perforations 19 of the portions11 and through the enlarged portion 15 of the latch, the said pin 6being sufli'ciently long to protrude slightly beyond opposite ends ofthe body portion '1 as shown in Fig. 2. A brazing flux of any suitableform or character, but herein shown in the form of washers 25, is placednear or upon the protruding ends of the pin 6.

As shown in Fig. 2 the pin 6 snugly fits the small diameters of theholes 19 and this is desirable in order to prevent the brazing materialor solder when subsequently melted from working through into theenlarged perforation 15 of the latch 7 or between the sides 11 of theneedle and said latch, thereby preventing the free swinging movements ofsaid latch. It is further apparent that if the insertion of said pivotpin into said apertures does not provide suflicient tightness to preventthe above from taking place, it is within the scope and purpose of thisinvention to exert pressure upon the ends of said pin in advance of theapplication of heat thereto so as slightly to compress said pin to causeit fully and tightly to fit said small perforations 19. The melting orbrazing action will follow said application of pressure at the propermoment.

- 'A"further "step in the operation is to apply heat and pressure to thepivot pinbut owing to the relative softness of the flux 25, said fluxwill first melt and flow into the perforations 19 around the ends of thepin. The metal of the pin 6 will next be softened to such an extent thata relatively slight pressure upon the ends thereof will cause said pinto be upset or enlarged substantially to fill the perforation 15 in thelatch as well as the substantial portions of perforations 19 in the sidemembers 11; including the countersunk ends of said perforations.Preferably the last three operations are performed nearly if notsubstantially simultaneously by the use of instrumentalities, such forexample as electrodes of an electric welding machine which when movedinto contact with the projecting ends of the rivet will cause anelectric current to pass through said pin and ef feet the heating andsoftening of the rivet as well as the melting of the soldering orbrazing material. The pressure applied by said electrodes to the pinwhen the latter has become sufiiciently heated results in the expandingor upsetting of the pin body to produce the enlargement 13 thereof andlikewise the heading of the ends into the countersunk portions of theperforations 19. The invention however is not limited to the use ofelectricity for heating purposes nor to the use of said electrodes forproviding the necessar pressure to upset said pin.

s the ends of the pivot pin expand,-under the combined heating and finalcompressing actions, into the perforations 19 the fused brazing materialwill form a rin encircling each end of the pivot pin and e ect thefusing or brazing of the ends of said pivot pin to the surroundingportions 11 of the needle making a solid permanent union between the twoparts, namely the pivot pin and needle body. The operation of heatingand compressing the pin 6 will be brought to an end before the enlargingof the journal portion of said pin 6 shall have been carried far enoughto cause it to engage too tightly the perforation 15 in the latch so asto leave said latch freely turnable upon said pivot.

Following the completion of the above steps the hardening and finalsmoothing up and polishing operations will take place.

' The invention is not limited to the particular embodiment shown.

Claims:

1. That method of making a latch needle which includes the forming of aslotted needle body with aligned perforations and a latch to fit saidslot having a perforation of relatlvely larger diameter than those ofsaid body, then in inserting a pin through the aligned perforations ofsaid needle body and latch in tightly fitting relation to the inner endsthereof, and in arranging a brazin material near said ends, and then inapp ying heat and pressure to melt said brazing material to cause it toencircle the ends of said pin, and to soften and compress said pin so asto cause it to enlarge and fill said perforations.

2. That method of making a latch needle which includes the inserting ofa pin through perforations in the needle body and latch thereof with theends ofsaid pin projecting slightly beyond opposite faces of said bodyand in arranging a brazing flux near said projecting ends, in applyingheat to melt said flux and soften said pin and in applying pressure toopposite ends of said pin while in said softened state to cause the pinto expand substantially to fill the perforations in said latch andtightly to fill the perforations of said bogy and to braze said pin tothe walls of said bo- That method of making a latch needle whichincludes the forming of a slotted needle body with aligned outwardlyflaring perforations and a latch to fit said slot having a perforationof relatively larger diameter than those of said body, then in insertinga pin through the aligned perforations of said needle body and latchwith the ends of said pin protruding slightly beyond opposite outerfaces of said needle body, then in placing collars of a brazing fluxupon both of said protruding ends and then in applying heat and pressureto opposite ends of said pins first to melt said brazing flux and causeit to flow into the perforations in said body surrounding said pin, thento soften said pin and finally to expand the pin substantially to fillthe enlarged perforation of said latch and tightly to fill theperforations of said body and to braze the ends of said pinkto saidbody.

4. That method of making a latch needle which includes the forming ofaslotted needle body with aligned outwardly flaring perforations and alatch to fit said slot having a perforation of relatively largerdiameter than those of said body, then in inserting a pin through thealigned perforations of said needle body and latch with the ends of saidpin projecting slightly beyond opposite faces of said body and inarranging a brazing flux near said projecting ends, and then in forcingelectrodes toward each other against opposite ends of said pin to causesaid flux to melt and fill the perforations in said needle bodysurrounding said pin and to soften said pin and finally compress thelatter substantially to fill the enlarged perforations in said latch andtightly to fill and braze said needle body and pin together.

5. That method of making latch needles which includes the forming of aslotted body with 'aligned'perforations in the sides thereof and informing a latch with a perforated end, then in inserting a pivot pinthrough the aligned holes of said body and latch, and in placing brazingmaterial adjacent the ends of said pivot pin and then in applying heatto melt said flux, and to soften said rivet, and in applying pressure toexpand said rivet body substantially to fill said perforations in 5 saidlatch and to fuse the ends of said pivot pin to said needle body.

6. That method of making latch needles which includes the forming of aslotted body with aligned perforations in the sides thereof adjacent theslot, the outer ends of said perforations being enlarged, in forming alatch with a perforated end, then in forcing a pivot pin through saidaligned perforations in said body and latch in tightly fitting relationto the inner smaller perforations in said body, in providing brazingmaterial for the ends of said pivot pin and then in applying heat andpressure to said pin and said brazing material to soften said pin and toeffect the up-setting and brazing of the ends thereof to the surroundingportions of said body, the inner ends of the perforations in said bodyand'said pivot pin forming a relatively tight fit to-prevent the meltedbrazing material from passing into the eye of said latch, and formingaround the perforations of said body outwardly tapered rings of brazingmaterial.

In testimony whereof, we have signedour names to this specification.

GEORGE W. MAYO.

, DELBERT F. MORSEv

